Editing Common year starting on Friday (section)

=== Gregorian calendar ===
In the (currently used) Gregorian calendar, alongside [[Common year starting on Sunday|Sunday]], [[Common year starting on Monday|Monday]], [[Common year starting on Wednesday|Wednesday]] or [[Common year starting on Saturday|Saturday]], the fourteen types of year (seven common, seven leap) repeat in a 400-year cycle (20871 weeks). Forty-three common years per cycle or exactly 10.75% start on a Friday. The 28-year sub-cycle only spans across century years divisible by 400, e.g. 1600, 2000, and 2400.

For this kind of year, the ISO week 10 (which begins March 8) and all subsequent ISO weeks occur later than in all other years, and exactly one week later than [[Leap year starting on Thursday|Leap years starting on Thursday]]. Also, the ISO weeks in January and February occur later than all other common years, but [[Leap year starting on Friday|leap years starting on Friday]] share this characteristic in January and February, until ISO week 8.
{| class="wikitable"
|+ Gregorian common years starting on Friday<ref name="math" />
!scope=row| Decade
! 1st !!colspan=2| 2nd !!colspan=2| 3rd !! 4th !!colspan=2| 5th !! 6th !! 7th !!colspan=2| 8th !! 9th !!colspan=2| 10th
|-
! [[16th century]]
|colspan=12| ''prior to first adoption (proleptic)'' || [[1582]] || [[1593]] || [[1599]]
|-
! [[17th century]]
| [[1610]] ||colspan=2| — || [[1621]] || [[1627]] || [[1638]] ||colspan=2| [[1649]] || [[1655]] || [[1666]] ||colspan=2| [[1677]] || [[1683]] || [[1694]] || [[1700]]
|-
! [[18th century]]
| [[1706]] ||colspan=2| [[1717]] ||colspan=2| [[1723]] || [[1734]] ||colspan=2| [[1745]] || [[1751]] || [[1762]] || [[1773]] || [[1779]] || [[1790]] ||colspan=2| —
|-
! [[19th century]]
| [[1802]] || [[1813]] || [[1819]] ||colspan=2| [[1830]] || — || [[1841]] || [[1847]] || [[1858]] || [[1869]] ||colspan=2| [[1875]] || [[1886]] ||colspan=2| [[1897]]
|-
! [[20th century]]
| [[1909]] ||colspan=2| [[1915]] ||colspan=2| [[1926]] || [[1937]] ||colspan=2| [[1943]] || [[1954]] || [[1965]] ||colspan=2| [[1971]] || [[1982]] || [[1993]] || [[1999]]
|-
! [[21st century]]
|  –  ||colspan=2|[[2010]] || [[2021]] || [[2027]] || [[2038]] ||colspan=2| [[2049]] || [[2055]] || [[2066]] ||colspan=2| [[2077]] || [[2083]] || [[2094]] || [[2100]]
|-
! [[22nd century]]
| [[2106]] ||colspan=2| [[2117]] ||colspan=2| [[2123]] || [[2134]] ||colspan=2| [[2145]] || [[2151]] || [[2162]] || [[2173]] || [[2179]] || [[2190]] ||colspan=2| —
|-
! [[23rd century]]
| [[2202]] || [[2213]] || [[2219]] ||colspan=2| [[2230]] || — || [[2241]] || [[2247]] || [[2258]] || [[2269]] ||colspan=2| [[2275]] || [[2286]] ||colspan=2| [[2297]]
|-
! [[24th century]]
| [[2309]] ||colspan=2| [[2315]] ||colspan=2| [[2326]] || [[2337]] ||colspan=2| [[2343]] || [[2354]] || [[2365]] ||colspan=2| [[2371]] || [[2382]] || [[2393]] || [[2399]]
|}

{| class="wikitable"
|+ 400-year cycle
|-
! 0–99
| 10 || 21 || 27 || 38 || 49 || 55 || 66 || 77 || 83 || 94 ||
|-
! 100–199
| 100 || 106 || 117 || 123 || 134 || 145 || 151 || 162 || 173 || 179 || 190
|-
! 200–299
| 202 || 213 || 219 || 230 || 241 || 247 || 258 || 269 || 275 || 286 || 297
|-
! 300–399
| 309 || 315 || 326 || 337 || 343 || 354 || 365 || 371 || 382 || 393 || 399
|}